Manufacture of electrical socket contacts



1957 s. T. DEAKlN MANUFACTURE OF ELECTRICAL SOCKET CONTACTS Filed Jan. 17, 1955 United States Patent or ELECTRICAL SOCKET CONTACTS" Stanley: Thomas Deakin, Ewell West,-England, assignor to The Edison Swan; Electric- Company Limited, London, England, a British. company Application January 17;19-551SeriaI 'No; 482,263

Claims priority,.application Great Britain February 1, 1954 This invention. relates to the manufacture of electrical socket contacts of the kind comprising a pair of resilient prongs adaptedto engage: opposite sides of contact pins and: has -animportant application. inter alia in contacts for sockets for thermionicvalves, discharge tubes and the like.

The resilient prongs of such contacts: are so arranged that when a contact pin is pushed between them they will press against the pin with: a good electrical connection whilst at the same time permitting ready disengagement of the pin.

Such contacts are usually produced from sheet metal by cutting and stamping processes and owing to the fact that contacts of this kind are normally produced in large quantities, it is important to reduce manufacturing operations-to a'minimum; I

The main object-of the invention is to simplify the manufacture of such contacts.

The present invention comprises a method of manufacturing socket contacts of the kind referred to, consist-ing in cutting a sheet metal blank which comprises a tag portion extending in the one direction and a pair of prongs extending in the opposite direction, separating the prongs by a shearing operation and contouring the prongs by a pressing operation in such manner as to rotate both the prongs at their root ends in the same angular direction about their individual longitudinal axes into parallel planes which are oblique to the direction of application of the pressure and the plane of the tag portion so that the free ends of the prongs are substantially opposite to each other.

4 The term angular direction implies that the ends of both prongs are rotated clockwise or anti-clockwise as the case may be, when viewed in the same longitudinal direction.

Preferably the rotation of the prongs is effected by a pressing operation in such a manner as to cause the radius of curvature of the bend formed at the root end of each prong to vary laterally in such a manner that the radius of curvature of the bend is greatest adjacent the line of severance and is least at the outside edge.

Preferably also the operation of severing the prongs and at least part of the contouring are carried out by a single pressing operation between suitably contoured dies.

The invention also comprises a socket contact member which includes a tag member extending longitudinally in one direction and a pair of prongs extending in the opposite direction, the prongs being twisted at the root ends in the same angular direction about their individual longitudinal axes into planes which are parallel to each other but twisted relative to that of the tag, and the lateral bends produced at the root ends of the prongs by'the-twisting operation have each a varying radius of curvature, the'radius of curvature being greatest at the centre, i. e., adjacent the line of severance of the prongs. According to a further feature, the ends of the prongs 2,7 7 9,01 1 Patenredjan. 2 2 ,1957

ice

. 2" are swaged so as to provide" ramp surfaces: on the two inner faces'which will assistthe' entry ofa pin or contact In orderthatthe invention may" be more clearly under stood, reference will now'be made to the accompanying drawings inwhich:

Fig: 1 shows a sane prior to the pressing operation by which it is contoured;

Fig 2' a plan view of a contact member after the pressing operation;

Fig; 3 -isa sfde view-of the contact membershown-in Fig: 2E and Fig. 4' is similarly an end view ofthe contact member shownin Fig'. 35am! Fig: iisaperspectiw view; I

In the drawing; the-'- reference "1' indicates: the tag: end of the contact member which" is formed with a" slot 21 whilst 3 and 1- are the prongs. During-the pressing operation the pron'gs' are severed along the line- 4 as shown in- Fig: 1, this severing being effected" by a shearing of the metal; p

Asabove explained", during the pressing operation the prongs are rotated about their longitudinal axes and looking at the'end of Fig; 3, ii e.', toward the prongend, itwill be appreciated that the prorrg's have been twisted in an? anticlockwise direction with the result that taking the view of Fig. 3 is a concave" bend at" 5 in the one prong and a convex bend at 6 in the other prong. These trends extend laterally across the root ends of the prongs and? aresuelr that the radius of curvature is greatest at theinside, i-i ex, adjacent the line of severance, as indicated at fl and i? and is least" at the outer edges of tEe-pi'ongs-as'iiidicat'e d at 9 -andflli I Referring now more particularly to" Fig '2, will he observed-that dining the pressing operation the prongs are both twisted and also moved laterally so that they overlay each other.

It has been found that the shaping of the bends 5 and 6 by which the radius curvature varies laterally has the effect of increasing the resistance of the prongs to deformation in the directions in which they are forced apart so that when a pin or contact is inserted between the prongs an increased pressure will be exerted on the pin as compared with a prong in which the bend is uniform across its lateral axis.

According to a further feature of the invention, the tips are swaged as shown at 11 and 12 so as to provide ramp surfaces 13 and 14 which will assist the entry of prongs or contacts.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A method of manufacturing socket contacts of the kind comprising a pair of resilient prongs adapted to engage opposite sides of a contact pin, consisting in cutting a sheet metal blank to form a tag portion extending in one direction and a pair of prongs extending in the opposite direction, and contouring said prongs by a pressing operation in such a manner as to rotate both of the prongs in the same angular direction relative to the tag portion through angles less than right angles about individual longitudinal and parallel axes into substantially parallel planes which are oblique to the plane of the tag portion so that the free ends of the prongs are substantially opposite to each other.

2. A method of manufacturing socket contacts of the kind comprising a pair of resilient prongs adapated to engage opposite sides of a contact pin, consisting in cutting a sheet metal blank to form a tag portion extending in one direction and a pair of prongs extending in the opposite direction, applying a pressing operation to the blank which forms a longitudinal out between the prongs and rotates both of the prongs at their root ends in the same angular direction relative to the tag portion and through angles less than right angles about their individual longitudinal axes into parallel planes which are oblique to the plane of the "tag portion so that the free ends of the prongs are substantially opposite to each other, and producing by the pressing operation bends in the prongs about axes of curvature extending laterally across the prongs whereof the radius of curvature is greatest adjacent the central longitudinal edge of each prong and progressively reduces to the outside edge and the bend being concave in one prong and convex in the other prong.

3. In the methol of manufacturing socket contacts of the kind comprising a pair of resilient prongs adapted to engage opposite sides of a contact pin, a stamping operation consisting in rotating both of such prongs at their root ends in the same angular direction relative to the tag portion about their individual longitudinal axes into parallel planes which are oblique tothe plane of the tag portion so that the free ends of the prongs are substantially opposite to each other, said stamping operation forming opposite bends about lateral axes in such a manner that the radius of curvature of each bend varies laterally across the prong so that the radius of curvature is greatest adjacent the central longitudinal line and is least at the outside edge, and swagingthe ends of said prongs so as to provide ramp surfaces on the two inner faces thereof for assisting the entry of a pin.

4. The method of manufacturing socket contacts of the kind comprising a pair of resilient prongs adapted to engage opposite sides of a contact pin, consisting in the steps of cutting a sheet metal blank to form a tag portion extending longitudinally in one direction and a pair of prongs extending in the opposite direction, and stamping lines of curvature about axes extending laterally across the root ends of the prongs, the two prongs being curved in opposite directions and the radius of curvature reducing progressively from a maximum adjacent the longitudinal axis to a minimum at the outside edges so that the prongs are rotated about their individual longitudinal axes into substantially parallel planes.

5. A socket contact member having a tag portion extending longitudinally in one direction and a pair of prongs extending in the opposite direction, said prongs being rotated in the same angular direction about their individual longitudinal axes into planes which are parallel to each other, the root ends of said prongs having opposite bends produced by the rotation thereof, said bends extending about axes of curvature extending laterally and each bend having a varying radius of curvature, the radius of curvature of each bend being greatest along the longitudinal center line of the contact member and decreasing progressively to the outside thereof.

6. A socket contact member having a tag portion ex tending longitudinally in one direction and a pair of prongs extending in the opposite direction, said prongs being rotated in the same angular direction about their individual longitudinal axes into planes which are parallel to each other but rotated relative to the plane of the tag, the root ends of said prongs having bends produced by the rotation of the prongs, said bends extending along lateral axes of curvature, each bendhaving a varying radius of curvature, the radius of such curvature being greatest along the center line of the socket member and decreasing progressively to the outside thereof, and the tips of the prongs being swaged outwardly.

References Cited in the file of this patent UNITED STATES PATENTS 2,476,429 Paules July 19, 1949 2,575,161 Deakin NOV. 13, 1951 FOREIGN PATENTS 538,801 Great Britain Aug. 18, 1941 584,884 Great Britain Jan. 24, 1947 

